The official Dragon Ball website’s twenty-fourth entry in “The Nearly Complete Works of Akira Toriyama” — an on-going series highlighting rare and important pieces of the author’s work over the years — is a citation from the 2002 book Genius PC Cram School.

The book explains how to draw comics on a personal computer, and begins with a joint Akira Toriyama & Ei’ichirō Oda feature explaining how to color, using pictures of Goku and Luffy as examples.

Toriyama first began thinking about using a computer to aid his illustrations in the mid-1990s, joking with fellow manga author Masakazu Katsura in the Shenlong Times accompanying Daizenshuu 7 in 1996:

But, once I get a Macintosh, it’ll be amazing. I’ll leave people like you in the dust, Katsura-kun. It seems like I’ll be able to do a lot of interesting things, too. If I say, “Put the main character in a running pose!” into the mic, maybe it’ll go ahead and draw it for me? That sort of thing would be the ideal.

In his 2003 Son Goku Densetsu joint interview with Katsuyoshi Nakatsuru, Toriyama noted the difference between his standard comic drawing process and the computer-aided illustration process:

No, I do comics with a pen and paper, same as always. I think comics are faster to draw with a pen, and then fill and tone by computer. But my illustrations are all done via computer. I even draw the lines on a tablet. Up to a certain point with the Kanzenban illustrations, I was drawing them with a pen, then scanning them and doing the coloring, but that also gradually became a nuisance, (laughs) so now I just use the tablet. When I started drawing the cover illustrations for the Dragon Ball Kanzenban, it had been so long that I had to start by looking for my pens. I turned the house upside down, shouting, “My Zebra pen-nibs are gone!!”

In his 2004 Dragon Ball Landmark interview, Toriyama noted how computer-aided drawing helped keep him going:

However, since I started using a Mac, my method of drawing illustrations has changed. In drawing it, even I think that it’s got no flavor, but without new things like computers, I’d probably have turned against drawing completely. I get the feeling that it’s probably because I discovered how enjoyable it is to express all sorts of things by computer, that I’m still able to keep drawing.

Toriyama recalled this same timeframe and feeling in his 2013 Chōzenshū 4 interview:

In terms of the way I drew the cover illustrations, for the first half, I’d scan the inked drawing into the computer, and color it using a program called Painter. For the latter half, I’d draw on a graphics tablet starting with the inking, and paint in the colors with a program called Photoshop. As for why I changed my drawing technique between the first and second half… it’s simply because I got tired of it. (laughs) I’m often told that coloring by computer “has no flavor”, but it’s not like I’m drawing a work of art here, so personally, I feel that right now, this is the best for me in terms of expression. If it weren’t for the computer, I suppose I would probably have gotten sick of it already, and would hardly be drawing anymore.